• 한국컴퓨터그래픽스학회논문지
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• 제26권3호
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• pp.69-77
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• 2020

본 논문은 3차원 가상환경에서 드로잉할 때, 사용자에게 위치 입력에 대한 피드백을 부여하는 효과적인 방법을 설계하고 그 성능을 측정하여, 피드백을 통해 사용자가 올바른 위치를 입력하는데 도움을 줄 수 있는지 확인하고자 한다. 주어진 선 형상을 핸드-헬드 컨트롤러를 이용하여 따라 그리는 실험에서 사용자에게 위치 입력 오차에 대해 세 단계의 시각, 청각, 촉각 피드백을 각각 제공하고, 어떤 피드백이 가장 효과적인지를 분석하였다. 피드백의 형태에 따른 위치 입력 정확도를 분석한 결과, 피드백은 특정 크기 이상의 입력 오류를 크게 감소시킬 수 있었으며, 시각과 촉각 피드백이 청각 피드백보다 효과적이었다.

• The Journal of Korean Physical Therapy
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• 제27권6호
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• pp.407-412
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• 2015

Purpose: This study aimed to evaluate changes in the balance ability of patients whose head positions were altered due to stroke. Subjects were divided into three groups to determine the effects of the training on dynamic balance and gait. Methods: Forty-two stroke patients were enrolled. The Visual Feedback Training (VFT) group performed four sets of exercises per training session using a Sensoneck device, while the Active Range of Motion (ART) group performed eight sets per training session after receiving education from an experienced therapist. The Visual Feedback with Active Range of Motion (VAT) group performed four sets of active range of motion and two sets of visual-feedback training per session using a Sensoneck device. The training sessions were conducted three days a week for eight weeks. Results: The comparison of changes in dynamic balance ability showed that a significant difference in the total distance of the body center was found in the VFT group (p<0.05) and Significant differences were found according to the training period (p<0.05). The comparison of the 10 m walk test showed that the main effect test, treatment period and interactions between group had statistically significant differences between the three groups (p<0.05). Conclusion: Head-adjustment training using visual feedback can improve the balance ability and gait of stroke patients. These results show that coordination training between the eyes and head with visual feedback exercises can be used as a treatment approach to affect postural control through various activities involving the central nervous system.

• 대한통합의학회지
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• 제8권1호
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• pp.113-124
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• 2020

Purpose : The purpose of this study was to investigate the effects of exercise intervention combined with 3D visual feedback and motion observation on postural alignment and cerebral cortical activity in subjects with forward head posture (FHP). Methods : The study included 28 participants with FHP, randomly divided into a 3D visual feedback plus motion observation group (n=14) or control group (n=14). The experimental group received corrective exercise combined with 3D visual feedback and motion observation for FHP, three times a week for four weeks. We examined cervical spine radiographs in the lateral standing position with both arms crossed to measure the craniovertebral angle (CVA) and cervical lordosis (CL). Relative alpha (RA) and beta waves (RB) were measured by wireless dry EEG. Results : The CVA value was significantly different between the groups, and the CL value was significantly different only in the experimental group. RA and RB values were not significantly different before and after intervention in the control group. RB values were significantly decreased before and after intervention in the experimental group. Conclusion : Based on the results of this study, we suggest that interventions combined with motion observation and 3D visual feedback may be effective as exercise methods to improve postural alignment and cerebral activity in subjects with FHP. Further research is required to generalize our results on technical supplementation complemented with 3D visual feedback devices.

• PNF and Movement
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• 제15권1호
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• pp.77-84
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• 2017

Purpose: This study aimed to investigate the effect of visual feedback training-for gradual weight shift in sit-to-stand training-on the balance and walking abilities of chronic hemiplegia patients. Methods: Twenty patients with chronic hemiplegia volunteered to participate in this study. The experimental group received visual feedback for gradual weight shift in the sit-to-stand training, while the contrast group followed the standard process for the sit-to-stand training. The evaluation of the balance and walking ability was conducted with the functional reach test (FRT), Berg balance scale (BBS), five time sit-to-stand (FTSTS) test, timed up and go (TUG) test, 10 m walk test (10MWT), balancia, activities-specific balance confidence (ABC) scale, and falls efficacy scale (FES). Results: In the results before and after intervention, there was a significant difference in TUG, 10MWT, ABC, and FES in the visual feedback training group (p < 0.05). In the control group, there was a significant difference in the 10MWT and ABC (p < 0.05). Also, in the evaluation of the postural fluctuations, the control group data showed a significant increase in Covar. The visual feedback group showed a significant difference in the W average. Conclusion: The visual feedback training group showed some improvement in terms balance and walking ability and on the ABC scale and FES. Therefore, if the diagonal progressive weight bearing exercise is combined with the various patterns and basic principles of PNF, it may be a more efficient intervention method.

• 한국전문물리치료학회지
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• 제19권3호
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• pp.40-50
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• 2012

The purpose of this study was to investigate the effect of visual feedback on the postural control of stroke patients, by systematically varying conditions of visual feedback [eye-open condition (EO) vs. eye-closed condition (EC)], and base-support (both-side support, affected-side support, and unaffected-side support). In this study, we allocated 41 stroke patients with no damage in the cerebellum and visual cortex who can walk at least 10 meters independently, and 35 normal adults who have no experience of stroke to the control group. Both groups were asked to perform a "sit-to-stand" task three to five times, and their postural control ability was measured and compared in terms of asymmetric dependence (AD) instead of the traditional symmetric index (SI) in the literature. The results showed that although both subject groups maintained better postural control in the EO condition than in the EC condition, the patient group appeared to be more stable in EC than in EO when they were required to perform the task of the support condition given on the affected side. These results implied that visual feedback can impair stroke patients' postural control when it is combined with a specific support condition.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.940-943
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• 1996

In teleoperating, as seeing the monitor screen obtained from a camera instituted in the working environment, human operator generally controls the slave arm. Because we can see only 2-D image in a monitor, human operator does not know the depth information and can not work with high accuracy. In this paper, we proposed a traded control method using an visual sensor for the purpose of solving this problem. We can control a teleoperation system with precision when we use the proposed algorithm. Not only a human operator command but also an autonomous visual sensor feedback command is given to a slave arm for the purpose of coincidence current image features and target image features. When the slave arm place in a distant place from the target position, human operator can know very well the difference between the desired image features and the current image features, but calculated visual sensor command have big errors. And when the slave arm is near the target position, the state of affairs is changed conversely. With this visual sensor feedback, human does not need coincide the detail difference between the desired image features and the current image features and proposed method can work with higher accuracy than other method without, sensor feedback. The effectiveness of the proposed control method is verified through series of experiments.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.235-240
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• 2004

The equipment of industrial robot in manufacturing and assembly lines has rapidly increased. In order to achieve high productivity and flexibility, it becomes very important to develop the visual feedback control system with Off-Line Programming System(OLPS). We can save much efforts and time in adjusting robots to newly defined workcells by using OLPS. A proposed visual calibration scheme is based on position-based visual feedback. The calibration program firstly generates predicted images of objects in an assumed end-effector position. The process to generate predicted images consists of projection to screen-coordinates, visible range test and construction of simple silhouette figures. Then camera images acquired are compared with predicted ones for updating position and orientation data. Computation of error is very simple because the scheme is based on perspective projection which can be also expanded to experimental results. Computation time can be extremely reduced because the proposed method does not require the precise calculation of tree-dimensional object data and image Jacobian.

• 대한물리치료과학회지
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• 제29권2호
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• pp.1-13
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• 2022

Background: This research was conducted to understand balance training in trunk control, balance, and walking in stroke patients. Design: Randomized controlled trial. Methods: The subjects included 40 stroke patients, of whom 20 undertook balance training using visual information and the other 20 undertook balance training using balance boards. Using visual feedback, the balance training group used a training program within the static balanced evaluation tool, while the balance training group trained using a balance board. All subjects underwent 20 mins of neurodevelopmental treatment, and both target groups underwent 10 mins each of balance training by using either visual feedback or a balance board. The treatment period lasted a total of 4 weeks, twice a day. Trunk control before and after training was evaluated with the Trunk Impairment Scale. Balance capability was assessed by the Berg Balance Scale, Functional Reach Test, Timed Up and Go test, and Static balance measurement tool. Walking capacity was measured using gait measuring equipment, and cadence and velocity were measured. Results: Both groups showed a significant improvement in their interstitial control, balance, and gait ability after the experiments compared to before the experiments (p<0.05). The difference between the two groups was not significant. The visual feedback balance training group showed a more substantial improvement than the balance board training group. Conclusion: In this study, we found that the balance training combined with visual feedback contributes to improving trunk control, balance, and gait in patients with hemiplegia due to stroke. In addition to this, I believe that balanced training combined with visual feedback can be used as a training method when considering patients who lack interstitial control, balance, and gait ability.

• PNF and Movement
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• 제15권2호
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• pp.133-140
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• 2017

Purpose: This study compares the effects of treadmill gait training accompanied by visual feedback and general treadmill gait training on the gait and balance ability of patients with chronic stroke. Methods: A total of 11 patients with chronic stroke were randomly divided into either the treadmill gait training accompanied by visual feedback group (six patients) or the general treadmill gait training group (five patients). The gait and balance ability of the two groups were measured before and after the interventions using the functional reach test, the Timed Up and Go (TUG) test, Berg's balance test, and the Biodex balance test. The treadmill gait training accompanied by visual feedback group performed the exercise under the supervision of a therapist after first being provided with a hat and a goal that was devised for the purpose of providing visual feedback information. The interventions were applied to the respective groups for four weeks. For the statistical analysis, we conducted a Mann-Whitney test to compare the results between the two groups. Additionally, the Wilcoxon test was used to compare the results from before and after the intervention in each group. Results: The treadmill gait training accompanied by visual feedback group showed a significant difference in terms of the functional reach test after the intervention when compared to the general treadmill gait training group (p<0.05). Although there was no significant difference, the treadmill gait training accompanied by visual feedback group showed a larger improvement in the TUG test, Berg's balance test, and the Biodex balance test than the general treadmill gait training group (p>0.05). Conclusion: The results of this study suggest that treadmill gait training accompanied by visual feedback can be used as a beneficial intervention scheme for the recovery of the gait and balance ability of patients with chronic stroke.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.610-615
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• 2005

Visual servoing is the fusion of results from many elemental areas including high-speed image processing, kinematics, dynamics, control theory, and real-time computing. It has much in common with research into active vision and structure from motion, but is quite different from the often described use of vision in hierarchical task-level robot control systems. We present a new approach to visual feedback control using image-based visual servoing with the stereo vision in this paper. In order to control the position and orientation of a robot with respect to an object, a new technique is proposed using a binocular stereo vision. The stereo vision enables us to calculate an exact image Jacobian not only at around a desired location but also at the other locations. The suggested technique can guide a robot manipulator to the desired location without giving such priori knowledge as the relative distance to the desired location or the model of an object even if the initial positioning error is large. This paper describes a model of stereo vision and how to generate feedback commands. The performance of the proposed visual servoing system is illustrated by the simulation and experimental results and compared with the case of conventional method for dual-arm robot made in Samsung Electronics Co., Ltd.